Method for seamless session transfer of a mobile station

Abstract

In the method, a source base station sends first information to a target base station. The first information indicates a sequence number of a first data unit in a sequence of data units undelivered to the mobile station by the source base station. The source base station also sends the target base station second information. The second information indicates data units, after the first undelivered data unit in the sequence, that have been delivered to the mobile station by the source base station. The second information may further indicate portions of the first undelivered data unit that have been delivered to the mobile station by the source base station.

1. A method for transferring a mobile station from a source base station to a target base station, comprising:
 sending first information indicating a sequence number of a first data unit in a sequence of data units undelivered to the mobile station by the source base station; and 
 sending second information indicating data units after the first undelivered data unit in the sequence that have been delivered to the mobile station by the source base station. 
 
   
   
     2. The method of  claim 1 , wherein the second information further indicates portions of the first undelivered data unit that have been delivered to the mobile station by the source base station. 
   
   
     3. The method of  claim 2 , wherein the second information identifies undelivered portions of the first undelivered data unit to indicate portions of the first undelivered data unit that have been delivered. 
   
   
     4. The method of  claim 2 , wherein the second information includes undelivered portions of the first undelivered data unit to indicate portions of the first undelivered data unit that have been delivered. 
   
   
     5. The method of  claim 2 , wherein the second information indicates a protocol used by the source base station to form the data units into transmission units for transmission to the mobile station. 
   
   
     6. The method of  claim 1 , wherein the first information includes the sequence number of the first undelivered data unit to indicate the sequence number of the first undelivered data unit in the sequence of data units. 
   
   
     7. The method of  claim 1 , wherein the first information includes a sequence number of a delivered data unit to indicate the sequence number of the first undelivered data unit in the sequence of data units. 
   
   
     8. The method of  claim 1 , further comprising:
 sending data units from the source base station beginning with the first undelivered data unit. 
 
   
   
     9. The method of  claim 1 , wherein
 the sending first information step is performed by a network gateway of a source network; and 
 the sending second information step is performed by the source base station of the source network. 
 
   
   
     10. A method for transferring a mobile station from a source base station to a target base station, comprising:
 receiving first information indicating a sequence number of a first data unit in a sequence of data units undelivered to the mobile station by the source base station; and 
 receiving second information indicating data units after the first undelivered data unit in the sequence that have been delivered to the mobile station by the source base station. 
 
   
   
     11. The method of  claim 10 , wherein the second information further indicates portions of the first undelivered data unit that have been delivered to the mobile station by the source base station. 
   
   
     12. The method of  claim 11 , further comprising:
 transmitting data to the mobile station beginning with the undelivered portions of the first undelivered data unit. 
 
   
   
     13. A method of transferring a mobile station from a source base station to a target base station, comprising:
 sending data of a first granularity to the target base station; and 
 sending information from the source base station indicating data undelivered to the mobile station by the source base station at a second granularity, the second granularity being different from the first granularity. 
 
   
   
     14. The method of  claim 13 , wherein the information indicates a protocol for creating data of the second granularity. 
   
   
     15. The method of  claim 14 , wherein the information indicates the second granularity. 
   
   
     16. The method of  claim 13 , wherein the information indicates the data undelivered to the mobile station by the source base station at a second granularity by indicating the data of the second granularity forming one of the data of the first granularity that have been delivered by the source base station to the mobile station. 
   
   
     17. The method of  claim 10 , wherein the information includes the second granularity data undelivered to the mobile station by the source base station. 
   
   
     18. A method of transferring a mobile station from a source base station to a target base station, comprising:
 receiving data of a first granularity from the source base station; and 
 receiving information from the source base station indicating data undelivered to the mobile station by the source base station at a second granularity, the second granularity being different from the first granularity.